Sumitomo U103709 Jobber Drill Bit Letter J Solid Carbide

Product Description

The SUMITOMO U103709 is a jobber-length drill bit sized to Letter J (0.277 inches / 0.2770 decimal inch) and manufactured from solid carbide with a dual TiAlCr and TiSi coating. It is designed for high-performance metal cutting in demanding production and machining environments. The 135-degree split-point geometry reduces walking and lowers thrust requirements at entry. With an overall length of 4.2913 inches and a flute length of 2.2047 inches, this bit fits standard jobber-length toolholders. It is installed and used by machinists, tool-and-die professionals, and CNC operators working in metal fabrication and precision machining.

This drill bit is suited for cutting cast iron, stainless steel, and alloy steel in both manual and CNC drilling applications. The 5xD flute-to-diameter ratio supports deeper hole drilling relative to diameter. Coolant-through capability makes it appropriate for high-speed, high-feed operations where heat management is critical. The straight-cylindrical shank with an h8 tolerance fits precision collet chucks and drill chucks used in machining centers and drill presses. Typical use cases include production drilling in job shops, aerospace component machining, and automotive manufacturing where tight tolerances and tool life consistency are required.

Key Features

• Solid carbide construction for rigidity and wear resistance in hard metal applications
• Dual TiAlCr and TiSi coating for elevated heat resistance and extended tool life
• 135-degree drill point angle reduces entry thrust and minimizes walking
• Coolant-through design supports high-speed and high-feed drilling operations
• Tapered web configuration for improved chip evacuation and core strength
• h8 diameter tolerance on straight-cylindrical shank for precise collet fitment

Compatibility

Designed for use in standard collet chucks and drill chucks accepting a 0.2812-inch straight-cylindrical shank, compatible with CNC machining centers and drill presses configured for jobber-length solid carbide tooling in metal cutting applications.

Installation Notes

Installation should be performed by a qualified machinist or CNC operator. Ensure the spindle is fully stopped and the machine is powered down or in a safe-stop state before changing tooling. Seat the shank fully and evenly in the collet or chuck to the recommended grip length to avoid runout. When using coolant-through capability, verify that the coolant system is connected and pressure is set according to the machine tool specification before beginning the cut.